Automatic reservation system of the code type



Dec. 16, 1952 FileC1 y 2. 1950 12 Sheets-Sheet 1 PL\ ooooooooooooooooooooooooooooooI SPACE TRAIN 1 a 5 7 9 11 13 15 17 19 21 23 25 27 29 31 ooooooooooooooooooooooooooooooo COACH 310 ooooooooooooooooooooooooooooooo--19]! ooooooooooooooooooo-oooooooooooo SEATS ooooooooooooooooooooooooooooooo 312 ooooooooooooooooooooooooooooooonyj'fj 0oooooooooooooooooooooooooooooo ISU ooooo'oooooooooooooooooooooooooo O ER 310 ooooooooooooooooooooooooooooooo 2S1] ooooooooooooqoooooooooooooooooo BERTHS ooooooooooooooooooooooooooooooo 416 ooooooooooooooooooooooooooooooo 2,5715 ooooooooooo'oooooooooooooooooooo IJ IKE 5297114. I ACCOMMODATIONS J COACH SEAT Q Q SINGLE BEDROOM LOWER BERTH Q Q DOUBLE BEDROOM UPPER BERTH Q @DRAWING ROOM PARLOR sEAT Q MASTER ROOM X COMPARTMENT Q Q #i ROOMET'TE Q Q DUPLEX Q Q EXTRA Y ifiKE 5 Z- I I 4 UE QQ/ 12D Fzgcjfi 4E Xpp JAN JULYE" A 0-AP APR OCT| 1 BO 1 I FEB AUG| O YFLJO MAY NOV| a 0O MAR SEPTI E0 JUNE DEC: F0 4-- 60 (W2 CANCEL p 41s- 5 HQV P VIE 32 INVENTOR. 5E Q ACTIVE Q l? Jackal Q/C'LP BY TD 0 M Fig? 2 HIS ATTORNEY A. P. JACKEL AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Dec, 16, 1952 12 Sheets-Sheet 2 Filed July 22, 1950 w en? Office INVENTOR. Arthur P. Jgzclz'el H15 ATTORNEY Dec. 16, 1952 A. P. JACKEL AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July 22, 1950 12 Sheets-Sheet 5 Fig? 5B. ApmakRJackez HIS ATTORNEY Dec. 16, 1952 A. P. JACKEL 2,622,142

AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July 22, 1950 12 Sheets-Sheet 4 IN V EN TOR. FigI Al bllll? Jackel mfw HIS ATTORNEY IN V EN TOR. Ari/2UP Ja cliel 12 sheets-sheet 5 15D 16D 5P 4P 5P )VlEf/V a Fir- A. P. JACKEL AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE rlgi Dec. 16, 1952 Filed July 22, 1950 HIS ATTORNEY Dec; ,16, 1952 A. P. JACKEL AUTOMATIC RESERVATION SYSTEM 0F THE CODE TYPE T 1 mm) 21 111W l/jza -12. kw P1 11/1 52 V v g bzvs afil M -)15T-; j zsraa INVENTOR. 19 55: Amffi arRJaqfi'el- By 40 M HIS A TTORNEY Dec. 16, 1952 A. P. JACKEL 2,622,142

AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July 22, 1950 12 Sheets-Sheet '7 M NM'J N B1 To Fiy 5A) mmvron Arthur I? Jackel H 15 A TTORNEY 16, 19 52 A. P. JAGKEL 2,622,142

AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July v22, 1950 12 Sheets-sheaf. 8

INVii'NTOR. FLg 4B. Arlzurfl Jae-[rel BY w-ZM His ATTORNEY Dec. 16, 1952 A. P. JAC KEL. 2,622,142

AUTOMATIC RESERVATION SYSTEM 01 THE CODE TYPE Filed July 22, 1950 12 Sheeifs-Sheet 9 XP YP ZP GNP IN VEN TOR.

Y Arthur R Jacket 0 war HIS ATTOHNI7Y A. P. JAcKEL.

AU'IOMATIC RESERVATION SYSTEM OF THE cons TYPE Filed July 22, 1950 Dec, 16, 1952 12 Sheets-Sheet 10 w a v Q w f w "d @w M N11 M 11 m l R w b m 1 d w 4 d N d w a d i m *2 I d b 4 a 0% b Iv G B .iilll b am i J m m N N 4 a R w m a b m 2 d M 2 LI, d n a 2 i=0; w a J z N .TL 5 d afi e 0 d Y I Z I M N N B 2 Fig HIS ATTORNEY D le, 1952 a A. P. .MCKEL 2,622,142 Y AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July 22, 1950 12 Sheets-Sheet 11 Office 0177' 011' 15s 1P0 Station 1L1 A 1L2 Fig 7 Intermediate Statz'an- W N 1T 16 MT 2'! a UUHFBH FR BP L02 LP ivwzgu z B Q41 5 Fig? 6.

' INVENTOR.

Arthur R Jackal HIS A TTOHNE' Y Dec. 16., 1952 A. P. JACKEL AUTOMATIC RESERVATION SYSTEM OF THE CODE TYPE Filed July 22. 1950 l2 Sheets-Sheet 12 Office m n -w------ ---b l mwU 2 ST fill fiw m H M 1 v a+ L i p HT r 1 2 1 a. u m L 1 #U i E r r PLv\ Z Z M a g N m 2 H m d 4 m s i 9 m a m W m n v 1 a U ...-b:d a u a .W nm wfl 9 IL git Station Request C'odev w Qfi 7 1 id my T m g l- 8 m 7 6 L 5 4 d 1 J 1 w L R we m 3.

izvvizzvron. Anibal P .fackel Fig? 12 H15 ATTORNEY Patented Dec. 16, 1952 AUTOMATIC RESERVATION sYs'rEMoF THE CODE TYPE Arthur P; Jackel; Penn Township, Allegheny County, Pa.,-assignor to Westinghouse Air Brake Company, acorporation of Pennsylvania ApplicationJ uly- 22,'1950, Serial N 175,451

Claims;

Theobject of my invention is theprovision of a system ior-selecting-and transmitting'itemsof information posted at a central station, to anyoneof" a plurality of remote'stations, and in the 'specific-embodiment shown; theapparatus of- 'myinvention comprises an improved automatic reservation system for facilitating thesale or reservation of transportation accommodations. Moreparticularly, my invention relates to an improved remote control'systemby-means of whichagents'at a large number of remotestations are enabled, by positioning certain control devices," to sendcode -messages -to a central ofiic'e without interference; each message constitutinga request forinformation storedin a central reservation board as to the availabiliy ofdifferent types of accommodations on aselecteddate on-a--particular train or-'trip.- Upon the reception of each request code, a 'replycode is transmitted automatically from the oifice to the sending stationby'm'eans of which a'series of visual indicators iscontrolled to indicate to the agent Whether or noteach of the difierent types of accommodation or "space-provided on the -selected trainer trip,"are available on the selected date.

My invention includes a code communication system having a coding unit at the ofiiceandat each station of the all-relay step-by-step type for the transmission and reception of codesignals, which is a modificationof the system identified as the time -code'systemdisclosed'in my LettersPatent of the United' states-No." 2,411,375, issued November 19, 1-946, forRemote Control Systems.

A-ieature of the presentinvention comprises transmitting contact at the station to seize the office coding'unit and to cause a request code to be transmitted to the ofiiceby the coding unit at the-initiating station, followed by areplycode which the oiiice coding unit transmits automati callyto such station. This apparatusis soarranged that when stations on different line circuits initiate request codes simultaneously, or iat a time when the ofiice coding unitis 'in usefithe various line circuits are connected'to the ofiice coding unit one at a timeso as-to enablethe'stations on different lines to transmit their codes in a predetermined sequential order without interference. In addition, each station which has transmitted one of a series"of successive codes is prevented from transmitting -a -se'cond code until the series is completed.

A further feature of-this line 'circuit'-system resides in provisions by which intermedia'te'sta tions may be included in each of the radial line circuits; that is, .eachofithe line circuits Which extends from a remote station to the central office may be used byrapluralityiof serially connected stations as in the "system of my- .pri'or patent. Another feature is that each station may include a pluralityof-agents consolestfor' controlling the same station coding unit so asto enable a plurality of agents at difierentlocations 1n the same station to "communicate-with the ofiice'over the same line "circuit one -'at a time without interference.

The line circuit system of my invention is adapted to employ existing long-distancecom munication circuits used jointly for telephone communication or the like, each of my line cir-' cuits being alternatively of. the'two-wire central battery type-,or of the four-wire'carrierJcurrent type. A feature of my invention resides in'the provision of repeaters-of a novel type :forex tending the length of the line circuit sections,-:in eluding one of the -2--2 type for connecting twotwo-wire circuits, repeaters of the 24typeland of the 42 type for connecting a two-wire bat-- tery circuit to a four-wire'carriercurrent-c circuit, andone OI the 4r-4: type for connecting two fourwlre circuits.

In accordance'with a further feature of' my invention the central office apparatus" m'ay be modified to employ a "plurality of 1 office coding units with separate connections to the-central reservation' board, so as to permit simultaneous communication between the oflice and 'two or more stations without interference, even thoug h connections are made for the transmission Of'll'iformation posted in the same sections of the may seize an idle"codingunit'which normally 3 is associated with stations of another group.

In addition to the line circuit system, my invention includes improved apparatus units suitable for use in a system of the type described, and an improved arrangement of coding apparatus for reliably performing a desired sequence of selecting operations rapidly and in a straightforward and logical manner while minimizing the liability of error.

I shall describe one form of apparatus embodying my invention and various modifications of portions thereof, and shall then point out the novel features of the system of my invention in claims.

In the accompanying drawings, Fig. 1A is a view of a portion of the reservation board employed at the central ofiice for the storage of train information, and Fig, 1B is a vertical crosssection of a portion of Fig. 1A showing three of the plug receptacles and one of the removable plugs.

Fig. 2 is a front view of the console or control panel provided for each agent at a station.

.Figs. 3A to 3E, inclusive, comprise a diagram of the circuits at the central office, in which Fig. 3A shows typical connections between the office coding unit and the communication lines which radiate from the office, Fig. 3B shows the control portion of the ofiice coding unit, Fig. 30 shows the counting relays of the oflice coding unit, Fig. 3D shows the register and selector relays which are governed by the difierent request codes, and Fig. 3E shows the circuits for one of a plurality of similar rotary stepping switches, of which one is provided for each section of the reservation board of Fig. 1A for the purpose of establishing connections for enabling the transmission of reply codes to be governed in accordance with the condition of selected ones of the plug switches of Fig. 1B.

Figs. 4A, 4B, and 4C comprise a diagram of the circuits at a typical agents station, in which Fig. 4A shows the control portion of the station coding unit and th line connections, Fig. 4B shows the counting relays of the station coding unit, and Fig. 4C shows the local circuits and apparatus included in each of the consoles of Fig. 2.

Fig. 5 is a diagram of circuits comprising a modification which may be substituted for Fig. 3A to provide line connections for two sets of the apparatus of Figs. BB-SE, connected to the same reservation board. This modification enables two agents on any two of the lines to establish communication with the reservation board at the same time.

Figs. 6 to 11, inclusive, are diagrams of various line circuits for use with the system of my invention. Fig. 6 shows a typical two-wire central battery line circuit connecting the ofiice apparatus of Fig. 3A with the station apparatus of Fig. 4A; Fig. '7 shows the circuits for a repeater of the 2-2 type which may be interposed in the line circuit of Fig. 6; Fig. 8 shows line connections for the apparatus of Fig. 4A which may be interposed in the line circuit of Fig. 6 for the control of apparatus at intermediate stations, and indicates how a plurality of stations may be connected serially to the same line circuit; Fig. 9 shows a typical four-wire carrier current line circuit, employing currents of two different frequencies fl and f2 for the two directions of transmission; Fig. 10 is a circuit plan for a repeater of the 24 type which may be interposed between the office apparatus of Fig. 6 and the station apparatus of Fig. 9; Fig. 11 is a circuit plan for a repeater of the 42 type which may be interposed between the ofiice apparatus of Fig. 9 and the station apparatus of Fig. 6; and finally, Fig. 12 is a diagram of the line signals constituting a typical request code and the resulting reply code.

Similar reference characters refer to similar parts in each of the views, and in lieu of showing the local sources of current for energizing the various devices, these are identified by the reference characters B and N, designating the positive or supply terminal and the negative or commonreturn terminal, respectively.

The reservation board of Fig. 1A is located at a central office or reservation bureau where the train diagrams are kept and where tickets are sold or reservations made for all of the trains listed on the board. The sale or reservation of space is efiected in the conventional manner, and as heretofore, involves the writing of a ticket number and an identification of the purchaser on one of the cards of the diagram for the corresponding train and date. When all of the space of a given type for that train and date is sold or reserved, and also when due to a nonuniform schedule the space is not provided on certain dates, the reservation clerk inserts plugs in the corresponding receptacles to indicate that the space is unavailable.

One purpose of the reservation board is to facilitate the local sale of tickets by enabling the clerks at the central reservation bureau to quickly ascertain what space is available on any train for each day of a three-month period begimiing with the current date, thereby avoiding the delay which would otherwise be incurred due to the necessity for locating and making a search through the file of train diagrams.

The reservation board of Fig. 1A comprises a plurality of sections ISU, ZSU, etc., including one for each type of accommodation listed in the upper portion of the agents console of Fig. 2. Each section SU comprises a plurality of similar unit portions or panels including one for each car or group of cars of a train carrying the corresponding type of space, which have the same destination. Each panel contains 93 switches each comprising a receptacle in which a plug PL may be inserted to open a normally closed contact, as shown in Fig. 1B. The receptacles as shown are arranged in three rows of 31 each, identified by the letters X, Y, and Z and assigned to dilferent months as indicated by the legends opposite the push buttons XP, YP, and ZP in Fig. 2. The numbers 1 to 31, inclusive, at the top of the board designate the days of the month designated by the receptacles in the corresponding vertical columns. Above these numbers a single row of dummy receptacles is provided in which a single plug PL is inserted to mark the current day of the month. If the current month is January, for example, the fact that no coach seats are available on January 5th on train 310 would be indicated by the presence of a plug PL in receptacle 5 in row X in the panel for train 310 in section lSU. If that is the current date, the receptacles 5 to 3! in row X in each of the panels designate the 5th to 31st of January, the receptacles in rows Y and Z identify dates in February and March, respectively, and receptacles l to 4 in row X identify dates in April at the end of the three-month period. It will be apparent that on any date except the first of the month the receptacles of one row will designaterpprtions of twodifferentmonths and .that.

each "receptacle will. designate a. day in four different months in the course of a year, as indicated'by the designations of the"month push buttons in Fig.2. It will be understood that where reservations are made for a 31 or 62 day period, only one or two rows of receptacles are provided in each panel and in the former case the month selector buttons are not needed.

The principal object of the automatic reservation system of my invention is to render the information .posted on the reservation board as readilyavailable to any agent at a branch oflice where tickets are sold and also to agents in distant cities as to the local personnel, and with this in View, each receptacle is provided with a normally closed contact, the opening of which manifests that a plug hasbeen inserted to indicatethat thecorrespondingspace is unavailable. The saleof spaceis effected in the conventional manner by telephone communication between the agent and a reservation clerk-at the central office after the desired space or an acceptable alternative has been shown to be available by operation of the reservation system. The advantage of the system resides in a saving in time inmaking a selection of space which is sufficient to materially reduce the cost of sales, and in the fact that it reduces the use of other communication facilities.

Each agents console, as shown in Fig. 2, includes. in its lower portion a combination of dials and self-latching push buttons which may be positioned to .designate each different train and date and to initiate the transmission of a request code to the oflice the elements of which identify such train and date. The control devices comprise a date dial DD, having 32 positions, Nos. 1 to 31 of which correspond to the days of a month, the three month push buttons XP, YP, and ZP, already mentioned, a train dial TD for rotating a cylindrical drum about a vertical axis to any one of 32 positions, identified by numbers l to 32 on the dial in each of which the drum is adapted to display train designations at eight different levels identified by the letters A to H, and finally, a group of eight self-latching push buttons AP to HP, inclusive, for selecting the train of which the designation is displayed at the corresponding level. It will be evident that each space occupied by a train designation may be identified by its coordinates such as 32-1-1 for the space occupied bythe train number 416 in Fig. 2.

The control portion also includes certain auxiliary apparatus, comprising a cancelling button CNP, a code indicator lamp SE which is lighted steadily when a code is stored fortransmission and "intermittently when a code is being transmitted or received, a push button CLP by which the code system may be caused to operate a call signal to enable the agent to call a reservation clerk to the telephone, and a lamp CLE for indicating the response of the equipment to the operation ofbutton CLP.

Each request code comprises a series of 16 steps or code elements, as illustrated in Fig. 12, in which steps 1 to 15 are either long or short as determined by the energized or deenergized condition of the corresponding one of a series of transmitter control circuits having the terminals IA to-v IA, which, as shown in Fig. 4C, are either connected to one terminal B of the local source of current or left open, depending upon the positions-of the dials and push buttons. As will be clear from Fig. 40, the circuits IA to IEA are arrangedin-groups for; control by'theg-difierent; dials and buttons, and the. circuits of .eachzgroup may be energized in various binary code combinations. corresponding to the total number ofpush v:buttons or dial positions.

In setting up a. code combination, the train button comprising -one of the group of buttons. AP HPis'operated last. and the code is initiated by picking up a starting relay CA, Fig. 4C, .over

a contact 65 controlled by a latch bar which.

The typical request code illustrated in.Fig.-12

is for the 16th of March (orofJuneyseptember or December, whichever is within the 93 day period beginning with the current date) forispace on train No. 310,-posted in sections "I'SU and ZSU in the reservationboard of Fig. 1A. It is to be understood that this train number is-inthe train drum position havingthe coordinates l-A, consequently it will appear in row A upon the rotation of the train dial TD of Fig. 2 one step clockwise from position'32 to position 1. As will be clear from Fig. 4C,-pressing'button ZP in Fig. 2

opens the connection to wire 2A only, consequently the first step of the code will be longand the second step short, as shown'in Fig. 12. The date dial DD is rotated degreesto position 16, corresponding to the 16th day'of the "month, where cam No. 1 opens the connection to wire 3A, while the cam contacts connected'to wires 4A-IA are closed so that the third'stepwill be short and steps 4.to 7 will belong; 'di'al TD in position 1 opens'the connections to wires 8A to 1 2A, and the pressing of button 'AP opens the connections to wires I 3A to I5A, and momentarily closes contact 65, making each of the steps 8-15 a short step as shown in Fig. 12, and also picking up relay CA to initiate the transmission of the request code.

In response to a request code, selectors at the central ofl'ice establish connections with the plug switches of the reservation board for the corresponding date and train, and cause the immediate transmission of a reply code to the station at which therequest code originated, of the type illustrated in the lower'portion of Fig. 12, during which a reception connector relay CC in the console in which the request code originated is operated to render a series of indicationstick relays lK-ISK responsive to the 'energization of wires lB-I5B on the successive steps of the reply code,'to light an indication lamp such as IKE in the upper portion of the console, for each type 3f tavailable space on the designated train and A feature of my invention is that each code initiated by the operation of a relay CA is stored by that relay until a communication circuit to the office is established. whereupona transmission connector relay CB, controlled byrelay CA, causes the transmission of a request code. The line connections are maintained and a reception connector relay CC is operated by relay CB on the 16th step of the request code so that'each request code is followed by a reply code without interruption of the connection between the oflice and the station of origin. An advantage of this arrangement is that the station identifying code elements heretofore required in code communication systems of this character are not needed,

removing a limitationilas to the number of- 'stations which may use the same set of'ofice' apparatus. V

A feature of the agents console of my invention is that the indications displayed as the result of the transmission of a reply code may be identified as belonging to the particular train and date designated by the last request code transmitted from the console, by reference to the positions of the dials and push buttons in the lower portion of the console. This is by reason of a provision of a lookout relay KD in Fig. 40 which governs the lighting of the series of lamps AE to HE for illuminating the selected position on the train drum. Lamp UE is located back of the exposed position of the drum DD and is normally lighted to illuminate the number displayed by that drum. One of the lamps AE to HE becomes lighted when the corresponding train button is pressed to illuminate the train number displayed at the corresponding level on the train drum. Relay KD is controlled over contacts actuated by the drums DD and TD and by the buttons at the left of the console in such manner that the indication relays IKIK are released upon a change in position of any of the control devices except the buttons AP-HP, while the operation of one of the latter buttons cancels the stored indications due to the operation of relay CA. It follows that the indications of the available space persist only as long as the control devices are left in positions identifying the train and date to which the indications apply.

For a general understanding of the selecting portion of the code equipment at the ofi'ice it will sufiice to point out that in response to each long step of a request code, a corresponding one of a series of storage relays lP-ISP at the ofiice, shown in Fig. 3D, is picked up with the same effect as if the station wires lA-I5A were connected directly to the wires lD-I 5D in the pickup circuits for these relays. It follows that in the case of the code illustrated in Fig. 12, only the relays IP and 4P-IP are energized, and as may be readilytraced from Fig. 3D, relays IP and 2P prepare a circuit from the supply wire 55 to wire 60 for a month relay 3M, Fig. 3E, selected by button ZP, relays 3P-1P prepare a circuit from wire 56 to wire [6U in a group of circuits l-32U, identifying the 16th day of the month, relays 8P-l2P prepare a circuit from wire 51 to wire iS identifying position 1 of the train drum, and relays l3P-I5P prepare a circuit AG for relays AIG and A2G identifying the level A on the train drum which are energized over wire 55 to pick up a selector relay IAS for the train 3'10 in question.

It will be understood that a selecting relay S, identified by a prefix IA to 32H, corresponding to the coordinates of the various positions on the train drum, is provided for each train destination posted, and that the circuits of Fig. 3D, although shown in condensed form, are adapted to provide connections for 32 groups of eight selector relays each.

For each unit panel in the reservation board of Fig. 1A, a selector comprising a rotary stepping switch such as the one identified as IS'II in Fig. 3E. is provided, these being of a conventional type having four banks of .40 contacts each. The contact points Pl-P3l of three of the banks (identified as lXl, IYI, and IZI) are con nected to the plug switch contacts PLl-PL3I of the panel, for the corresponding dates and levels, the other terminal of each plug switch being connected to the supply terminal B of the local source of current. The contacts PI-P32 of the fourth bank III are connected to correspondingly numbered terminals of the wires l-32U, one of which terminals is supplied with energy according to the date selected, as already explained. Each stepping switchis actuated by a stepping magnet SM having a self-stepping control circuit which includes a contact which opens when the magnet is energized and having its terminal identified by the designation of the stepping switch on a terminal board in Fig. 3D. The terminal board is equipped with adjustable jumpers so arranged as to enable the control terminal of any stepping switch to be connected to one of the contacts a. to h of the selecting relay S for any train, so that energy will be supplied to the stepping switch magnet to initiate its step-by-step operation whenever the selecting relay S for the train to which the corresponding panel is assigned becomes energized.

This arrangement has the advantage of facilitating changes in the posted information in response to changes in schedule or make up of trains. The posting of train 310, for example, involves merely assigning to the train an available selector relay lAS; marking the train number on an available panel in each section of the reservation board which designates a type of accommodation provided by train 310; inserting jumpers in the terminal board referred to, so as to connect the contacts of relay lAS to the stepping relay control circuits for these panels, and informing the agents to mark the train number in the space having the coordinates l-A on their train drums. Likewise, the stepping switch lSTZ for the second panel in section ISU is controlled by the selector relay ZAS, consequently the corresponding train {number 310 should appear in the space having the coordinates Z-A on the train drum.

Although the agents console is normally connected to a line circuit associated with a particular reservation board, it may readily be switched to another line circuit extending to a reservation board in another city upon which the information posted relates to trains not listed on the agents train drum. In such cases the agent is provided with a chart having the coordinates I to 32 and A to H upon which the trains on the distant reservation board are listed to enable him to move his train drum to the correct position and to operate the proper train button.

On the 16th step of the request code being described, the selector relay IAS picks up, and completes circuits over its contacts a and b to energize the control terminals for the stepping switches ISTI and 2ST! for the top panels in the sections ISU and 2SU of the reservation board of Fig. 1A, so that these stepping switches all advance to a position where their magnets SM are held energized over circuits completed over one of the holding circuit terminals i-32U and the contact arms of the lower banks such as IUI In the present case, wire I EU is supplied with energy so that the switches stop on point P16 and the month selector relay 3M, which also is energized, connects the contact arms of the Z banks of all of the stepping switches to the correspondingly numbered wires I C-I5C. In the present example, switch lZl connects terminal B to wire IC and switch 2Z| connects terminal B to wire 2C, but Wires 3C-l5C are left open because no other stepping switches are operated.

The wires IG-IC are included in the control circuits for the oilice code transmitter which when supplied with energy cause the corresponding steps of a reply code to be long steps, as indicated in Fig. 12, with the result that energy is supplied to the wires lB-I5B of Fig. 40 to pick up corresponding ones of the indication relays IK-I5K at the receiving station.

It will be seen that the agents console has one lamp for each section SU of the reservation boardand that in the example being described the indication lamps IKE and ZKE are lighted due to the closing of circuits at the omce over the control wires IC and 2C for sections ISU and 2SU, respectively, which are supplied with energy over the contact points of a particular plug'switch PIS. in each section, for the month selected by relay 3M and for the day selected by the stepping switches lSTI and 2ST! actuated by the selector relay IAS for train 310.

At the end of the reply code, the various code system relays release and each operated stepping switch advances to its normal position in a conventional manner due to the closing of the contact a of an oif normal switch ONS. A checking relay STCK, Fig. 3A, is provided with a pickup circuit closed during the transmission of a reply code and a stick circuit including wire I6C an'd'the contacts 17 of all of the oii normal switches ONS. Relay STCK serves to open the coding circuits and to operate a buzzer in the event any stepping switch fails to return to normal within the time period of the 16th step of a reply code.

As shown in Fig. 40, the agents console also includes a cancelling button CNP for deenergizing'the equipment by opening the connection to terminal N of the source, and a thermal relay THR which disconnects terminal N in the event the starting relay CA or the delivery relay CC remains energized for an abnormally long period.

Additional agents consoles at the same station may be connected to the station coding unit for noninterfering operation by connecting the wires "-20, inclusive, of each added console similar to Fig. 40. to the wires IlA-ZQA of the one which is connected directly to the station coding unit, and by connecting the wires I-ISA and I-IfiB to corresponding terminals in each console.

The apparatus also includes means by which the agent is able to send a special check code of all long steps to cause the return of a similar reply code to operate all of his indication relays for checking purposes.

The check code of fifteen long steps is transmitted by operating button HP only. Buttons XP, YP, and ZP are not operated and dials DD and TD are placed in positions 32 as shown in Fig. 40, so that terminal'B is connected to each of the wires I AI5A. Each of the relays IP-I5P of Fig, 3D pick up, causing relay TCK, Fig. 3E, to be energized over wire 6|, in place of a selector relay S and a month relay M. Energy is supplied over the contacts 11-0 of relay 'ICK to each of the transmitter control terminals IC-I5C so that each of the indication relays IK-I5K is energized in response to this reply code.

The coding apparatus at the office and stations by which the codes of Fig. 12 are transmitted and received is a modification of that of;my prior Patent No. 2,411,375 and functions in a generally similar manner. The coding units at the oflice and station are generally similar and corresponding relays bear similar designations, each oifice relaywhich has a'counterpart 10 at the'stationbeing distinguished by the prefix 0.

The'station coding unit, shown in Figs. 4A and 4B, is governedby a line relay R of the biased polar type which responds to code impulses of a given polarity only, as illustrated in Fig. 12, and by the operation of its contact a energizes a series of counting relays I to 8 one at a time on the corresponding code steps. On step 8, a chain repeat relay OR is opera-ted and then the counting relays I to I operate through'a second cycle on steps 9 to 15, and'a final counting relay I6 is operated in place of relay '8 on the'16th step. Contacts 0 and dot the counting relays govern the transmitter control circuits IA-I5A above'referred to and'their contacts e and f'gove'r'n receiving circuits IB-I5B for the control of the indication relays IK-IEK which pick up to register the long stepsof a code.

Contact I) of the line relay R controlsa series of timing relays IL, 2L, LP, LB, and LBS for governing the coding operations. All of these relays pick up at the beginning of thefirst step of a code, and then relays IL and 2L are energized alternately over contact I) in its opposite positions. Relay IL releases on each long oddnumbered step, while relay 2L releases on each long even-numbered step so as to operate the relays by which the long steps of a received code are registered. The release of relay IL or 2L opens the circuit for relay LP, the release of which at the transmitting station measures the length of the long steps. Relays LB and LBS remain picked up for the duration of'a code and release successively on the 16th step. These relays serve to space" the successive codes and to reset theapparatus properly to normal in the event a code'is interrupted.

The station coding unit is conditioned to transmit a request code by energizing a master relay M,'Fi'g, 4A, which activates a transmitter relay IT and an auxiliary'relay 2T, which relays are controlled over back contacts of the odd and even-numbered counting relays respectively to generate the short code steps, and over front contacts of relays IL or 2L and LP togenerate the lon'g'code steps. The master relay Mis picked up over wire IT by the starting relay CA in the a'gents console, but only when'the coding apparatus' is in its normal at rest condition. The transmitter relay IT transmits the code either by the operation'of its contact I), which is included in the'line circuit in series with'the'line relay R, or by'the operation of acontact d included'ina second line circuit. The'statio'n coding unit also'includes'a transmission totalizing relay MT which picks upon the last-step of a requests code and shunts the transmitting contacts of relay IT to 'enable'the office transmitter relay OIT to transmit the reply code,'and a reception totalizing relay DT which picks up on the last step of the reply code to release relay MT.

The oifice coding unit, shown in 'Figs. 3B'and 3C, includes counting, timing, and transmitter relays similar to those at the station, controlled by a similar line relay PR, and also include an additional timing relay LBP. In addition, the office coding unit includes a delivery relay D which picks up on the first step of a request code and renders the storage relays IP-I5P responsive on the successive steps of that code, and alsoincludes a reception totalizing relay ODT and a-repeater DTP controlled by'the delivery egcaamm relay D'which' pick upon the last step 'of a' re: quest code. Relay ODT removes the shunt from' the transmitting contacts of relay OIT to enable it to control the line circuit in place of the station transmitter relay IT, and relay DTP op-' crates the office master relay OM to initiate the ated by the associated relay PC by which the office coding unit is connected in sequence to each of the line circuits which have codes stored for transmission.

The two-wire type of line circuit which is a feature of my invention is illustrated by the one having the line terminals ILI and IL2, in Fig. 3A, which are connected by line wires to terminals LI a'nd'L2 of Fig. 4A. This line circuit is shown in its entirety in Fig. 6, from which it will be seen that the positive terminal LB of the line battery at the central oflice is normally connected to the lower line wire which extends to the line terminal L2 at the station, while the negative terminal LN of the line battery extends to terminal LI, and that theline circuit is open at contacts I) of relays IT and MT. The transmitter contact b of relay IT closes when a request code is initiated, with the result that current flows through the biased polar relays INR and R in opposite directions so that relay I NR is operated but not relay R. This occurs at the point indicated by the legend N in the code diagram of Fig. 12. As explained hereinafter in connection with Fig. 3A, the office coding unit in its normal at rest condition supplies energy over wire 35 and the reverse contact a of relay INR to the pole changer relay IPC, so that if the office coding unit is in condition to receive the code, relay IPC picks up, and as shown in Fig. 6. its contacts insert the coding unit line relay PR in the line circuit in place of relay INR, reversing the line polarity so that relays PR and R pick up in series to begin step 1 of the reouest code, which is then transmitted by relay IT as illustrated in Fig. 12. On the 16th step of the reouest code, relay MT picks up to shunt the transmitting contact of relay IT and relay ODT picks up to remove the shunt from the transmitting contact of relay IT, enabling relay OIT to transmit the reply code illustrated in Fig. 12. Relay IPC is released by the totalizing relay OMT at the beginning of the 16th step of the reply code, and the coding units then assume their normal at rest condition with all relays released as shown. The slow release relay I SS, however, remains in its picked-up position after terminal B is reconnected to wire 35 and holds the circuit for relay INR open long enough to enable relay 2P0 or SP0 to be picked up in preference to relay IPC, for the reception of the next code, in the event relay 2NR or 3NR stands reversed.

It will be noted that during the line open periods of the reply code transmitted by relay OIT, the line wires are connected together over front contact b of relay ODT and back contact I) of relay'OIT. This provides a discharge path for energy stored in the line during the line closed period and by reducing the code distortion, adapts the system to use line circuits in cable.

In Fig. 6 a device designated LPF is shown connected in series with the line wires at each end of the circuit. It is to be understood that these are conventional low pass filters for enabling the same line wires to be used simultanecusly for voice frequency or carrier current communication.

Referring now to Fig. 7, the novel repeater here shown comprises two biased line relays R0 and RS and a line battery of suitable voltage. When the repeater of Fig. 7 is interposed in the line circuit of Fig. 6, voltage is supplied to terminals ILI and IL2 by the office line battery of a polarity to pick up relay INR but not relay R0, when contact a. of relay RS is closed, and is supplied to terminals LI and L2 by the line battery at the repeater station of a polarity to pick up relay RS but not relay R, when contact b of the station transmitter relay IT is closed. That is, relay IT picks up relay RS, which picks up relay I NR, with the result that relay IPC picks up to reverse the polarity supplied toterminals ILI and IL2 so that relays PR and R0 pick up in series. Relay R0 reverses the polarity supplied to terminals LI and L2 so that relay R picks up in series with relay RS. During the transmission of a request code, relay RS repeats the operation of relay IT, relays PR and R0 repeat the operation of relay RS, and relay R is picked up by relay R0 and released by relay IT. During the transmission of a relay code, relay RS is held energized by the closing of contact I) of relay MT; relays PR and R0 repeat the operation of relay OIT, and relay R repeats the operation of relay R0. It will be seen that interposing the repeater delays the response of relay R to the operation of the associated transmitter IT by the time of operation of relays RS and R0, but since quick acting line relays are used, this is of negligible efiect at the code speeds employed, which conventionally is at the rate of ten short steps per second.

Referring now to Fig. 8, one or more intermediate stations arranged as here shown may be interposed in the line circuit of Fig. 6, the additional equipment needed comprising a line relay R2 in series with the line, three timing relays LP2, LE2, and LBPZ controlled by relay R2 and a line sectionalizing relay MP for connecting the coding unit to the line. The timing relays function like the relays L in the coding units, to enable a request code to be initiated only when the line circuit is in its normal at rest condition. Under this condition, relay MP picks up to disconnect the remote station upon the energization of the master relay M to initiate a request code, and is held energized by relay M or by the totalizing relay MT until the end of the corresponding reply code over circuits which will be readily under stood from the drawings.

Each of the connector relays PC in Fig. 3A is adapted to connect the oflice coding unit to a four-wire carrier current line circuit as illustrated by the circuits controlled by relay 3P0, shown separately in Fig. 9.

For controlling the carrier currents, the relays IT, MT, I6, O'IT, and ODT are each provided with a second transmitting contact (1. When contact d of relay IT is closed, an oscillator 050-! at the station supplies current of a suitable frequency over a one-way line channel through filters I which selectively pass that frequency to an amplifier AMPI, the output of 13 which. is rectified:,.in: a. conventionahma-nner; and supplied to relay 3NR.or PR in-placeofjbattery current.

The closing of contact at ofrelay ITjthus serves to initiate transmission by energizing-relay .3NR, whichpicks up relays 31C and 38S in the-usual manner and conditions relay PR to receive: a request code transmittediby relay; IT.,

Whenrelay 3P0 picks up,1it suppliescurrent ofa second frequency from an oscillatorO-SCJ over another one-way line channel through the selective filters f2 to an amplifier AMP-2,, the output of which; is rectified and supplied-to relay R, which therefore responds to'the operation of contact 1) of relay IT during the; transmission of the request code in the same manner, as in Fig. '6.

During the transmission of the reply code, contacts d of relays l6 and MT areclosed so that oscillator, OSC-I supplies carrier current steadily to amplifier AMP-l, this being coded by-contact b of relayQIT to operate-relay PR. At thistime contact d-of relay-CDT is.open,;and-thexoperar tion of contact (1' of, relay OIT causes: oscillator OSC-Z' to supply coded current to amplifier AIVE-Z to operate re ay R.

twill be evident that the re1ays:PR and'R are operated in the required manner in" each instance.

The interchangeability of the'two'types of line circuit will be evident'from a consideration of the repeaters of Figs. 10 and 11, eachf which includes two line relays RS and RO'similarto'those of Fig. 7.

When the repeater of Fig. is interposed between the right-hand portion of Fig. 9 and the left-hand portion of Fig. 6, the closing :of contact at of the station transmitter IT operates relay RS by rectified current from oscillator OSC-I, and relay RS picks up relay INR at the ofiice with the result that relay IPC picks up to reverse the polarityof the current supplied to relay R0) and then relays PR-and R0 pick up inseries. Relay R0 causes rectified current from oscillator OSC-Z at the repeater station to, be supplied to the station line relay R, whichpicks upover contact I) ofrelay. IT. During the transmission of 'a request code, relay RS repeats the operation of relay IT, relays PR and R0 repeat the operation of relay RS, and relay R is picked up by relay R0 and released by relay IT. During the transmission of a reply coderelay RS is held energized by relay MT, relays. PR and R0 repeat the operation of relay OIT, and relay Rrepeats the operation of relay RO, all of which is the same as in the case of Fi '7.

When the repeater of Fig. 11 is interposed between the left-hand portion of Fig. 9 and the right-hand portion of Fig. 6, the closing of contact b of relay IT operatesrelay RS, which supplies rectified current from an oscillator OSC-I at the repeater station to relay 3NR, with the result that relay EPC picks up to supply current from oscillator OSC2 to pick up relay R0, which picks up relay R. During the transmission of a request. code,.r.elays RS and R repeat the operation of relay; IT and relay PR. repeats the operation of relay RS. Duringthe transmission of a reply code, relays PR and R0 repeat the operation of relay OIT and relay'R repeats the operation of relay R0. It will be seen that the repeater of Fig. 11 is free from the slight amount of code distortion produced by those of Figs; '7 and 10.

When the number of line circuits and stations is. large, it may bedesirableto provide two...co,ding

units :andsets or selecting; apparatus-at theoffioe suchzas shown in'Figs. 3AT-3E' for, scanningthe same reservation board, in order to reduce-delays in operation. For example, asshown. in Fig. 5, a coding unit CU-I may serve certain line circuits having the terminals ILI-IL2, 3LI-.3L2, etc., and another coding unit CU-Z may serve another-group of linecircuits having the terminals 2LI2L2, lm-4L2, etc., the stepping switches controlled by each coding unit having connections to the same setof ,plug. switches in Fig. 313, so as to enable any two stations, in different. groups, to transmit codes at the same time.

If the. two coding units are independentvof one another, it may occur-that all of thestations which have codes to transmit ata given time are in the same group and that the oifice coding unit for the other group is idle at the time.

In the modification shown in Fig. 5, means are provided by which either coding unit is available foruse-by all of the stations of: both groups. In addition to the connector relay PC for connecting each line circuit to the office coding unit with which it'is normally-associated, as in Fig. 3A, an auxiliary connector relay PCA is provided for connecting the line circuit to the other coding unit if1this is available but the one to which it is connected by its relay PC is not available.

For example, if coding unit CU-I is idle as manifested by the energization of its terminal35, the operation of the line relay INR, for example, picks up relay IPC to connect the line terminal ILI to the coding unit terminal 40 and thence in Fig. 3B through relay PR to the battery terminal LB, and to connect the other terminal ILZ of the same line circuit to the other battery terminal N.

If, at this time, the coding unit'CU-Z is also idle, energy is supplied from its terminal 35 momentarily over contact I) of relay INR to relay IPCA,.but due to the resistor in its circuit, relay IPCA. operates more slowly than relay IPC and does not pick up because its circuit is opened at back contact 6 of relay IPC.

Relay IPCA operates only in the event coding unit CU-! is in use and unit CU-Z idle, and when operated, connects the line terminal ILI to terminal ll! of coding unit CU+2 which is connected through. its relay PR to battery terminal LB, and connects terminal !L2 to terminal LN.

Similarly, the line terminals ZLI and 2L2 which normally are connected to coding unit'CU-2 by the operation of relay ZNR are connected to coding unit CU-I by the operation of this relay if coding unit CU-Z is in use and coding unit CU-I is idle.

Each relay PFA in Fig. 5 governs a station sequence relay SSA which like the relay SS prevents the reenergization of the associated relay NR at the end of acode provided some other relay NR is energized.

Having thus described the principal features of the automatic reservationsystem of my inven tion, I shall now describe in step-by-step fashion the operations involved in thetransmission and reception of a typical request code and of'the corresponding reply code. The code to be described is that illustrated in Fig. 12, indicating the availability of the space posted in sections ISU and ESU'of the reservationboard of Fig. 1A, for trainNo. 310 on March 15th.

As already explained, the agent rotates the date dial,.DD. of Fig.2 .to position 16, presses button 'ZP;.1T0.tates the train dial to position 1 where the train number 310 will appear at level A, and completes the selection by pressing button AP. The initial movement of dial DD or TD by operation of the 32 tooth cam shown in Fig. 4C (or the operation of the latch bar controlled by button ZP, whichever is operated first) picks up the stick relay KD over contact 62, 63 or 64 and thereby extinguishes all of the indication lamps that may be lighted by releasing all of the operated relays IK-l5K. The operation of button ZP releases button XP or YP, if latched down, and the operation of button AP moves the latch bar to release any train button that is latched down, and to complete a pickup circuit for the starting relay CA, which extends from terminal N at contact a of the cancelling button CNP over the contact of the thermal relay THR, through the winding of relay CA and thence over the latch bar contact 65 to terminal B at back contact a of relay CC.

The latch bar is arranged so that contact 6 closes momentarily when one of the buttons AP-HP is pressed even though the button is initially in its latched position.

Relay CA picks up and completes a stick circuit over its front contact a and back contact a of'relay CC, and the operation of contact e of relay CA lights lamp SE and releases relay KD, which by closing its contact 0 lights lamp AE back of the exposed train number in level A of the train drum in Fig. 2, to illuminate this number. By closing its contact 0, relay CA picks up the master relay M of the station coding unit over wire I! and back contacts of certain relays in Fig. 4A which contacts are included in the circuit to insure that the circuit will not be closed again until the coding unit has returned to its normal at rest condition. The closing of con tact d of relay M picks up the transmitter relay IT over a circuit which may be traced from terminal N through the relay Winding, back contact b of relay 2T, front contact d of relay M, back contact g of relay MT, wire 21 and thence to terminal B over back contacts 9 of the counting relays I, 3, 5, and I. Relay 2T picks up over front contact 0 of relay QT and contact of relay M. Relay 1T completes a stick circuit over its own front contact a and front contact e of relay M having one branch which extends to terminal B at back contact e of relay LBS, and another branch which extends over front contact b of relay 2T and thence as already traced over wire 21 to terminal B.

The closing of front contact b of relay M completes a circuit over back contacts d of relays LBS and ET, wire l8 and front contact b of relay CA to pick up relay CB, and when relay 21'' picks up its contact (1 completes a stick circuit over wire I9 to hold relay CB picked up. The closing of contact 1' of relay CB connects lamp SE over wire I 6A to terminal B at back contact 0 of relay LBS.

The closing of thetransmitting contact in or d of relay I T energizes the ofiice line relay lNR or 3NR for the associated line circuit as indicated in Fig. 6 or 9, provided a line circuit is available. Assuming that the line circuit is of the direct current type shown in Fig. 6, relay EPC is energized over the circuit from terminal N at contact at of the check relay ST-CK, Fig. 3A, contact b of a cut-out switch CB, the winding of relay IPC, back contact b of relay ISS, contact a of relay INR, and extending to terminal B over back contacts in Fig. 3B which when closed indicate that the oflice coding unit is in its normal at rest condition. Relay lPC picks up, completing its stick circuit which extends over its own front contact a, wire 37, and back contacts 0 of relays OMT and DTP to terminal B at back contact e of relay OLBS. Relay iPC energizes relay ISS, reverses the line polarity and releases relay INR. The reversal of line polarity constitutes a "go ahead signal for the transmitting station and marks the beginning of step one of the request code shown in Fig. 12. The line circuit as set up for the transmission of the request code may be traced from the line battery terminal LB, Fig. 3A, over wire 39, the winding of relay PR, back contacts b of relays DDT and OIT, wire 40, front contact b of relay IPC to terminal LI and over the upper line wire to terminal Ll, Fig. 4A, through the winding of relay R, over contact b of relay I T to terminal L2, over the return line wire to terminal [L2, Fig. 3A, and over front contact d of relay IPC to the other line battery terminal LN.

Relays R and PR operate in unison. In Fig. 4B, the counting relay I picks up over wire 23, back contacts b of relays LB and LBS, and the left-hand contact a of relay R, and in Fig. 4A, the timing relays IL an 2L pick up over the left-hand contact I) of relay R, energizing relays LP, LB, and LBS in cascade, while in Fig. BC, the counting relay OI is picked up by relay PR over a similar circuit including wire 43 and relays OIL and 02L pick up, and in addition the delivery relay D picks up over the circuit extending to terminal N over wire 36 and to terminal B over back contact (1 of relay OLBS and the left-hand contact a of relay PR. Relay D lights lamp RE to indicate the reception of a request code. Relays OLP, OLB, and OLBS pick up in cascade and relay OLB energizes relay LBP.

The closing of front contact (2 of relay OLBS connects terminal B over front contact a of relay D and front contact of relay OLB to relay D, completing a stick circuit over which relay D is held energized. Front contact 7 of relay OLB closes to maintain terminal B connected over back contacts C of relays DTP and OMT to wire 37, to hold relay IPC energized, and the closing of front contact I) of relay LBP completes a stick circuit over wire 38, to hold relay ISS energized. The closing of contacts 0 of relays LBP and D prepares circuits for energizing the register relays IP-I5P over wire 5| or 52 in response to the release of relay OIL or 02L during the long steps of the request code-and connects terminal B to wire NED to prepare stick circuits for the register relays.

The closing of front contact I) of relay OLB connects the left-hand contact a of relay PR to the wire 42 over which the odd-numbered counting relays are successively energized and thereby completes a stick circuit for relay OI, and the closing of contact 0 of relay OLB connects the right-hand contact a of relay PR to wire 44 over which the even-numbered counting relays are successively energized. The closing of front con tact of relay OLBS transfers the circuit for relay O-lL to the right-hand contact b of relay PR so that relay OI L becomes deenergized when relay OLBS picks up on the first code step.

In Figs. 4A and 4B, the counting relay circuits over wires 22 and 24 are prepared, and relay IL is deenergized, by the operation of the corresponding timing relays LB and LBS. In addition, the circuit for the code indicator lamp SE is extended over Wire 15A and front contact 0 of relay LBS to the right-hand contact a of relay 

